Em Sat, 11 Jan 2014 14:42:30 +0100
Frank Schäfer <fschaefer.oss@xxxxxxxxxxxxxx> escreveu:
> Previously, we've been assuming that the video endpoints are always at usb
> interface 0. Hence, if vendor audio endpoints are provided at a separate
> interface, they were supposed to be at interface number > 0.
> Instead of checking for (interface number > 0) to determine if an interface is a
> pure audio interface, dev->is_audio_only should be checked.
>
> Signed-off-by: Frank Schäfer <fschaefer.oss@xxxxxxxxxxxxxx>
> ---
> drivers/media/usb/em28xx/em28xx-audio.c | 15 +++++++++++++--
> 1 Datei geändert, 13 Zeilen hinzugefügt(+), 2 Zeilen entfernt(-)
>
> diff --git a/drivers/media/usb/em28xx/em28xx-audio.c b/drivers/media/usb/em28xx/em28xx-audio.c
> index b2ae954..18b745f 100644
> --- a/drivers/media/usb/em28xx/em28xx-audio.c
> +++ b/drivers/media/usb/em28xx/em28xx-audio.c
> @@ -243,11 +243,22 @@ static int snd_em28xx_capture_open(struct snd_pcm_substream *substream)
> }
>
> runtime->hw = snd_em28xx_hw_capture;
> - if ((dev->alt == 0 || dev->ifnum) && dev->adev.users == 0) {
> - if (dev->ifnum)
> + if (dev->adev.users == 0 && (dev->alt == 0 || dev->is_audio_only)) {
> + if (dev->is_audio_only)
> + /* vendor audio is on a separate interface */
> dev->alt = 1;
> else
> + /* vendor audio is on the same interface as video */
> dev->alt = 7;
> + /*
> + * FIXME: The intention seems to be to select the alt
> + * setting with the largest wMaxPacketSize for the video
> + * endpoint.
> + * At least dev->alt and dev->dvb_alt_isoc should be
> + * used instead, but we should probably not touch it at
> + * all if it is already >0, because wMaxPacketSize of
> + * the audio endpoints seems to be the same for all.
> + */
Actually, it should take into account only the analog case, since, in
digital mode, the audio comes via the MPEG stream instead.
Ok, it makes sense to return -EBUSY if one tries to use it while using
DVB.
>
> dprintk("changing alternate number on interface %d to %d\n",
> dev->ifnum, dev->alt);
--
Cheers,
Mauro
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